Accident Overview
While on downwind to land, both engines of the aircraft experienced a loss of power resulting from fuel starvation. Subsequently, control of the airplane was not maintained, and it impacted in an open clearing at a steep angle.
Fuel System Findings
Examination of the fuel system revealed that the fuel selector valve handles indicated a position opposite (180 degrees out) to the actual fuel valve position selected. No fuel was found in the left auxiliary tank, while evidence of fuel was present in the other three tanks. No indication of fuel or propeller rotation was found at the left engine, whereas fuel and some rotation were evident at the right engine. Neither propeller was feathered. The flaps were in the up position and the landing gear was down.
Maintenance History
A mandatory service bulletin (MSB) had been recently installed that involved the fuel selector valve handles. The MSB could not be performed as per the instructions. The mechanic modified the kit procedures, resulting in the selector handles being installed opposite to the fuel port position.
Conclusion
The accident investigation documented that the fuel selector handles were misaligned due to the maintenance modification, leading to fuel starvation in both engines. No additional causal factors were identified in the provided source.